Assiohob to westinghotjse electric



April 29 1924.

R. D. MGMANIGAL REGENERATIVE CONTROL Filed April 18 1922 l mm I lNvE'NToR, /aberf McMM/gd/ ATTORNEY Patented lgiprgze,1924.' i 5 1,492,137

i y STATES PATENT .FFICEL lnoinlam' nime/mou., 'or'mem onto, XSSLIGNBfowEs'rINenoUsis ELECTRIG @a mumble Cnam" ,A 'GQF'QEATQNQE EN-,Ngivmm v f Appuanbiiiid'epru 1s,"1s22;fsrino. 555,058.

To allwhom't WvyvOnCeM: n' Q main `idiving motorl is shown provided Be itknown-that L'ROBERT D. vMCMANI- f nwith vaniiirmuture Qi'andaa, series fieldmagnet v o`AL,`fa citizen of the United States,fandl a w'indingi, which isy oonnected, dring ino residenty ofV Logan, inthe county of Hocktori ',toiaftrolle 1con'du`ctor'4 eind a return 5 ingend rSteteof yOhimh'eve invented a new -oircuit'fmrk'ed f roundf; by the closure of 6 0 y and useful yIm rovement invRe eneretive theswitch 153.2 UvAmotor;generator set 6, com- Controls, `ofjvvhich the followingiisfpa'speci- -prising ,avinotors :71 andg. generator 8,'which yic'atonfgvr o ,f

yalemechenicellv connected by,r means of a f fMyfnventionrelates to motor-controlsys-shaftfi'9,isremployed tor energizethe field- Vl0 temsfendit hnsfparticulr relationtocontrol megnetwindingfxof the motor l duringreo5 ystems for Ygoverning theaoperton -cfa, .g'eneration Theauxiliar r motor 7 is promotor during regeneration.'vfl f, f f -videdfswithe plurelitylof eld-magnet Wind- Oneobject of my invention is to provide f mgszl()y Fand?, 11 endfanfarinaturelQ. The si control systemfforfstl motor whiehhelliinrlanxiliaryf'geerator 8 is provided with a pluibsurefthat, duringfregene'mtionythefbraking -frality LOife'ield-'magnet, windings :13 and 14 70 y torque yof thefmotorfwill be Substantially :a'nd y'aimait-lire;15."y Astabilizing resistor Y constant, lregrdless ofy relatively* greet #lemeybeoonnected in circuit with the archanges ini the ofthe motor.` 'A J mature 2j olf-the minmotor 11 bythe closure 1 l -Anotherobjeotiof'my-invention is to prooff mfswitchqfl.;afDurin regeneration, the k20 Vvide -ineens for so energizingthe ifieldfmagfswitcherfis opened fand t e; switch r17 closed, net-"winding of e motori during regeneravtheifebyproviding, tin-armature circuit from t'ion` that, uponv a deereese-` i'n the -current ground: throughi" stabilizing resistor 16, traversing the `armature circuitiofl` the inoswiteh' 17 endgarmatreto the trolley contor, a corresponding increase inthe ener- .ductorffi y; f, a L ,i 4 gizationof theffeld-'magnetwindingvrwill be Theaxilia'ry motor7 is energized by a 80 eieoted tov `seeiire the same braking torque. eircuitgwhih is esteblishedupon lthe elo- `VAnotherobjeet-ofmy invention is pro-k fsure: o-{a switeh-;fl'8 from thetrolley l oonvide an auxiliary generator for' sorienergiz- .gductor 4"thro'ughgthje switch'. 18, yseries fieldv ingl ,thei:eldflgnet'Winding-pf,eqnioton mzgnetlwindiiig 10 endzarmeturelQ of the I0 that thenvoltafge of theexcitmggenereborzfmotorfendifield-megnetywinding 13 ofthe RF ywill vary substantially ininwverse'lproportion generator 8 yto:feel.,returni,circuit yInerld to the 'curnttraversing theammature/of,ffGroundJ @When-,the armature 15. of the4 the main motor. w 'l nfgeliiertor 8,is Efdrivenhy the motory 7 the l ffiBrieyispeeking, my yinventioneinfnfirises.ogehuntftieldfmegnetfWinding*I4-inf thegen- 35 rovding a `inotjo'r-generetorfset end aAstab- .,{enaitorendge se' aratelyexoted eldfmagne .,liliiingresistonto v'tiythejux ofuthomain net'windmgg'llo fthemotor 7 areenergized .field-magnet `jvr'indiihg,015eduiving rmotore-byenmrent treversingthe armature 15. ;'l`he f'tduring ,regeneretie m-inversepmportieetoffeldfmaemtnmm :Spf-the; mam dwing 40m- Eor e=better understanding of 'my inven-gf-theqeiruit comprisingermatlirelo of 95 tion, refeecemey made. tojthe raceomther?? y, Berater destabilizing resistor 1 16,

`Lorf.=a1not(' i*control Systemnmnstnueted-imne-t-kdriving motonl isi rotetinget :thigh speed,

#,fthe@uxsofthefieldfinagnet Winding 3 of 100 Fig.125is aouirvejehartshovving he relathe motorr lywill vabe `relatively low, if the tion ofv the ,taotve etrtrand'speed'of a,.vvolta,ge=across ltheterminels of the armature motor-Ito thefeurrenetraversing,tsamainf.fliof5the@anxiliaryegeneretor,8 is constant.

i '.;e1d-ma.gqtjfwinding Aduring lef-egeneretion.,. Thetreaskongforitheluxof the field-magnet so Fig also shbwsthiegrelationofthe meiner, winding-becoinin ofreletively low/ value 105 mature cuir-rent,v vvoltage and exe-item, is that the/voltage ropeacrossthe Stablhzmg Q f4 power jto-k the current. traversing' the field-g resister;16,-v.4 p vill .be greater, other. vvconditions y 55,? Referring drevving, anrege magnet winding ofthe motorduhing"regen-1,y being theisamm'jgirhen fthe armature 2 is roeratiom M -v l --fe-tating at, mnelatlvely high ,speedQ/end, thus Y neretingianrelxatively heavy current .to 110 the line, than when it is rotating at a lower speed. The voltage drop across the resistor 16 is equal to the'product of the current traversing the resistor 16 and the value of the resistance thereof. The resistance vof the resistor 16 being constant, the voltage drop across the terminals thereof will increase directly as the current traversing the armature 2 of the main driving motor 1 increases. Assume that the voltage across the terminals ot the armature of the generator 8 is increased. then the voltage across the terminals or` the field-magnet Winding 3 will increase. The increased voltage across the winding 8 will increase the current traversing the armature 2 .of the main driving motor. This increase in current traversing the armature 2 will increase the voltage drop across the stabilizing resistor 16, and the -voltage across the terminals of the fieldmagnet winding 8 of the main driving motor 1 will decrease, thus re-establishing stable braking conditions. It is. therefore, apparent that, as the speed of the motor 1 decreases and, therefore1 the current traversing the armature 2 thereof decreases, the excitation of the field-magnet Winding 3 increases, thus increasing the load ofthe generator 8. If the voltage across the terminals of the armature 15 of the auxiliary generator 8 is constant, the increased excitation of the fieldmagnet winding 3 of the main driving motor 1 is not suiiicientto maintain substantially constant braking torque for the motor 1 as its speed decreases. Therefore, I have provided a generator having series characteristics whereby the voltage will build up, if the electrical load across the terminals of the armature thereof is increased. K

The series-wound auxiliary motor 7 decreases its speed as the load upon the armature 15 of the auxiliary generator 8 increases. The excitation of its shunt field- -agnet winding 14 increases, because of the rising voltage characteristic of the generator 8. The rising voltage characteristic of the generator 8 is caused by the currentV traversing the 'armature 12 of the auxiliary motor 7 increasing when the motor 7 is subjected to an increased load, thereby causingr the energization of the 4separately excited field-magnet winding 18 of thev auxiliary generator 8 to increase to compensate for the decrease in speed of the generator 8.

The field-magnet Winding 11 ofthe auxiliary motor 7 is so energized by the armature 15 ot the generator 8 that it prevents the speed ot the armature 12 of the motor 7 Vfrom becomingr excessive asthe load upon the generator 8 decreases. However, it is not so designed as to vmaintain the motor 7 at a constant speed, but rather to limit its speed variations to a predetermined value that is less than that of an ordinary series motor. The result of this arrangement of the connections of the motor-generator set is to secure a flat speed characteristic for the auxiliary motor 7 rather than a series characteristic.

The system of control is so constructed that the stabilizing resistor 16 acts not only as a stabilizer between the current of the held-magnet winding 3 and the current of the armature 2 of the main motor 1, but also as a regulator for the exciter. If the voltage ot the exciter 8 tends to increase, then the voltage across the terminals of the fieldmagnet Winding 3 increases, thereby increasing the current traversing the `armature 2 and the stabilizing resistor 16 and thus increasing the potential across the resistor 16 to compensate for the increase in voltage of the generator 8. If the speed ofthe generator 8 decreases because of a decrease in line voltage across the terminals of the motor 7 then the excitation of the field-magnet winding 3 of the main motor l decreases, and the regenerative current traversing the armature 2 of the main motor 1 and the stabilizing resistor 16 tend to decrease, but this decrease is counterbalanced by the reduced line voltage across the armature 2, thereby securing balanced-torque conditions.

Referring to Fig. 2 of the drawing, it will be noted that the curve marked T. E., illustrating the relation of braking effort in foot pounds to the value of the current in amperes traversing the main field-magnet Winding 3 of the motor 1 is substantially constant for a Wide range of speed of the motor 1.

The voltage of the auxiliary generator 8 (see curve marked Exc. volts) increases in value as the regenerative current (see curve marked Reg. Amp.) traversing the armature 2 of the motor 1 decreases.

The curves representing the speed of the main motor 1 and auxiliary motor 7 are designated as M. P. H. Reg. and M. G. R. P. M., lrespectively. It will be noted, by examining the curves M. G. R. P. M. and Exc. K. W. that the power furnished by the auxiliary generator 8 increases as the speed of the auxiliary motor 7 decreases.

From the above description, it is apparent that I have provided a system of control for a motor whereby substantially constant braking torque is secured throughout a wide range of speed during regeneration.

While I have shown my invention in its preferred form, minor modifications may be made in the arrangement of circuits and apparatus employed without departing from the spirit of my invention. I desire, therefore, to be limited only by the scope of the appended claims.

I claim as my invention 1. Ina motor-control system, the combination with a main motor having an armature and a field-magnet winding, of a resistor inseries relation with said armature during regenerative braking 'of said motor, an auxiliary generator having a plurality of field-magnet windings for energizing the ield-ma net'winding of said main motor, an auxiliary motor'having a plurality of field-magnet windings and an armature for driving said generator, one of the field-magnet windings of said auxiliary motor being energized by said generator and one of the field-magnet windings of said generator vbeing connected in 'series relation with the armature and a field-magnet winding of said auxiliary motor. i f f f main motor having an Varmature and a fieldmagnet winding, an; auxiliary generator, having a field-magnet winding and an armature, for energizing said main motor fieldwinding, -an auxihary motor, for driving said generator, having an armature, a series field-magnet.k winding vand a separately-excited field-magnet winding, said separatelyexcited field-magnet winding being energized by said generator and the Held-magnet winding of said generator being connected in series relation with the armature and another of the windings of said auxiliary 4 motor.

3. A motor-control system kcom rising a motor having anl armature and a eld-magnet winding, a generator, havin a plurality of iield-magnet windings yan an armature, for energizing said main motorv ieldmagnet winding, an auxiliary motor havin a plurality of field-magnet windings an an armature, and means for mechanically connecting said auxiliary motor to said generator,; one of the windings of ksaid gen-f erator and a winding and the armature of said*y auxiliary motor being connected in series relation and yoneof the windings of said generator and said auxiliary motor be- 2. A motor-control systemy comprising ,a

erative braking, of said motor,an auxiliary motor, having a field-magnet winding and anarmature, for driving said generator, one of the field-magnet windings of said generator being connected in series relation with the armature of saidiauxiliary motor, and the other of said generator field-magnet windings being connected in shunt relation t0 the/armature of said generator..

5. Ina motor-control system, the combination with a main motor having an armature and a field-magnet winding, of an auxiliary generator, having a plurality of fieldmagnet windings, for energizing said main motor field-magnet winding during regenerative braking of said motor, an auxiliary motor, having a field-magnet winding and an armature, for driving said generator, one of the field-magnet windings of said generator being connected in series relation with the armature of said auxiliary motor, and the other of said generator field-magnet windings being connected in shunt relation to the armature of said generator, and means, comprising a resistor in series relation with the main motor field-magnet winding, for automatically regulating the voltage of the auxiliary motor in accordance with the speed of said main motor armature.

In testimony whereof, I have hereunto subscribed my name this 5th day of April 1922.

ROBERT D. MCMANIGAL.

LA.; A 

